Trying to identify unknown gram + and gram - bacteria, cocci or bacilli

[mochi]

This first picture shows a gram stain of 2 unknown bacteria (one is gram +, and one is gram -). At first, it appeared that both the gram positive and gram negative bacteria were cocci. 

I then isolated the gram + from the gram - by plating on a phenylethyl alcohol agar and a MacConkey Agar. But the next pictures seem to show the gram negative bacteria (on the MacConkey Agar) to be bacilli...?

What do you guys think these bacteria are? I'm pretty much positive that the gram positive bacteria is cocci, but I'm not sure about the gram negative... :/

Thanks for your help!!!

This is the gram + unknown bacteria (plated on the phenylethyl alcohol agar). I'd say this is definitely cocci.

This is the gram - unknown bacteria (plated on the MacConkey Agar). This picture makes it look like bacilli... but it was hard to tell if it really was under the microscope. The first picture showed the gram - bacteria looking like cocci... I'm not really sure what it is... 

Do you guys know if the gram - is cocci or bacilli?

Thanks!

[hypervalent_iodine]

I am no expert in this, but is it possible that it is a coccobacilli? 

[mochi]

This experiment is for my microbiology lab class... not sure if it could be coccobacilli...

If it is a type of bacilli, it does not ferment lactose on the MacConkey Agar. 

This means (from the flow-chart), that it must be either: P. vulgaris, P. rettgeri, P. mirabilis, P. inconstans, P. aeruginosa, P. fluorescens, or P. mallei.

I am doing a methyl red test also to see if it ferments glucose, but I haven't seen the results yet. 

 

 

 

[VictorMedvil]

If you really don't know what type of bacteria it is do a DNA sequencing of the Bacteria after you sequence it you will know with 100% certainty what type of bacteria it is. But based on the fact that it is a pink Positive Gram bacteria I think it is E.coli.  and the purple negative gram Staph.

Edited July 11, 2018 by VictorMedvil

[mochi]

The possible bacteria in unknown vial are:

Gram positive: 

Bacillus cereus

C. Xerosis

Enterococcus faecalis

Lactococcus lactis

Micrococcus luteus

Staphylococcus aureus

Staphylococcus epidermidis

Gram negative:

E. coli

E. aerogenes

P. vulgaris

P. fluorescens

P. aeruginosa

 

The professor narrowed it down a bit for us. So there is only gram negative bacilli. 

 

 

@VictorMedvil Wait, I thought gram + stained purple and gram - stained pink...?

[PhilGeis]

Gram positive  looks like a coccus prob staph  - so confirm staph (catalse, coagulase to aureus or epi) ruling out Microcccus with oxidase, if no catalase then Enterococcus per list. 

 

Gram negative species are not going to be identified further by Gram stain.  If no fermentation on MacConkey - rule out E. coli and E. aerogenes (weak, give it  little time).   Culture on any simple agar medium should tell you if it's one of the others - Proteus vulgaris should swarm all over the plate, P. aeruginosa should show a green color, smell slightly of grapes and grow at 42C, P. fluorescens my produce pigment but doesn't grow at 42C.